Conventionally, when a liquid is dispensed by use of a liquid discharge regulator, the liquid is discharged, for example, via a nozzle of the dispenser. Note that a nozzle is typically made of a non-corrosive metal such as stainless. As a common way of preventing liquid drops from obstructing a discharging head of a nozzle, a water-repellent film is formed at the nozzle.
When a nozzle, which is made of a non-corrosive metal such as stainless steel, is continuously used without proper maintenance and, as a result, when a water-repellent film formed on a nozzle starts to come off, a liquid becomes likely to remain at a discharging head of the nozzle. This causes, when the liquid is dispensed as drops, (i) the size of a first drop to become large and therefore (ii) the overall amount and forms of the drops to be inconsistent. This phenomenon becomes particularly problematic in cases where a liquid is dispensed for (a) an attachment of an LED sealant containing a fluorescent material and (b) an attachment of a camera module requiring precision in the area of combining surfaces.
As a method for preventing a liquid from obstructing a discharging head of a nozzle as described above, there is a method in which a depressurizing mechanism called a suction bag is attached to a liquid discharge regulator so as to retrieve a liquid obstructing a discharging head of a nozzle. However, even a suction bag is incapable of sufficiently removing a liquid that is remaining at/obstructing a discharging head of a nozzle. Hence, continuous use of a liquid discharging nozzle inevitably leads to inconsistency in the amount and forms of liquids because liquids eventually remain at/obstruct a discharging head of the nozzle as a result of (i) stains becoming, over time, collected on even a water-repellent film or (ii) the water-repellent film physically coming off because of particles contained in the liquids. Note that the chance of the liquids obstructing the discharging head varies, depending on (a) how rough surfaces of inner and outer walls of the nozzle are and (b) the thickness of the walls at the discharging head. Therefore, there are nozzles made of non-metal materials such as ruby and ceramic in order to enhance processing details of the nozzles. These types of non-metal nozzles, however, are highly expensive. Thus, there is a demand for a technology that could carry out liquid discharge with consistency in a discharging amount while maintaining low costs.
Examples of liquid discharging heads (disclosed in Patent Literatures 1 through 3) for solving the problem encompass a nozzle 100. The nozzle 100 is made up of, for durability of a water-repellent film, (i) a nozzle plate 101, (ii) a foundation layer 102 provided on a surface of the nozzle plate 101, and (iii) (a) a plated film prepared by adding fluorine to a surface of the foundation layer 102 or (b) an organic water-repellent film 103 (see FIG. 5). Also, there are other disclosed technologies in which surfaces of nozzle plates are coated with fluorinated and silicon-based water repellents.